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how to show constellation of ofdm?

(joined July 2021)
Participant

Hi:
recently I uesd optisystem to build a CO-OFDM system with FSO channel, but I cannot get the OSNR and the constellation.
About the OSNR, the optical power meter after the FSO channel shows the noise power equals zero.
About the constellation, I dont know how to show the constellation after the OFDM demodulator. I see someone used a subsystem to show constellation, but I dont know what the subsystem has. Is it another communication system?

Responses (4):

    • #69675
      mackenzie fency
      Participant

      Hi:
      recently I uesd optisystem to build a CO-OFDM system with FSO channel, but I cannot get the OSNR and the constellation.
      About the OSNR, the optical power meter after the FSO channel shows the noise power equals zero.
      About the constellation, I dont know how to show the constellation after the OFDM demodulator. I see someone used a subsystem to show constellation, but I dont know what the subsystem has. Is it another communication system?

    • #69686
      Profile Photo
      Ahmad Atieh
      Moderator

      Dear Mackenzie,
      You may access the Constellation of the OFDM Demodulator through the Project Browser as shown in the attached image. You can measure the OSNR using the WDM Analyzer Visualizer at Default/Visualizer Library/Optical/
      Regards,
      Ahmad

      +1
    • #69689
      mackenzie fency
      Participant

      Dear Ahmad:
      Wow, it works! Thank u so much Mr. Atieh!
      But after I used WDM analyzer, there still one question:
      I used QPSK to build OFDM system, and the WDM analyzer always tells me signal power equals 0. Is this because of QPSK or because I used only one wavelength?
      If there is an offense, please forgive me.
      Mackenzie

    • #69690
      Profile Photo
      Ahmad Atieh
      Moderator

      Dear Mackenzie,
      there is no offense.
      I am not sure what the settings for the component in your project are. So, I can’t comment. However, you may place a power meter at the same port and check the power. You may email me your project as a zip file to ahmad.atieh@optiwave.com and I would check it out and comment.
      Meanwhile, please let me know which version of OptiSystem are you using and your affiliation.
      Regards,
      Ahmad

    • #69704
      mackenzie fency
      Participant

      okay, thank u Mr. Atieh!

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